Die head for thread-cutting tools



Oct. .19 1926.. 1,603,605

C.- JOBST DIE HEAD FOR THREAD CUTTING TOOLS Filed Sept. 30 1921 2 Sheets-Sheet 1 6 O A i u UR L M 0 u g? INVENT EIR fam'ao 1151mm Oct. 19, 1926.

C. JOBST DIE HEAD FOR THREAD CUTTING TOOLS Fi e T pL so 1921 2 Sheets-Sheet 2 INV'EJNT UR- Patented @et, 19, 1 .9%

unirsn stares CONRAD sense, or roLEno, on'cro, Assreivon TO THE TOLEDO, OHIO, A CORPORATION K NT-owners MACHINE 00;, or

or onro. I

DIE HEAD FOR THREAD-CUTTING TOOLS.

Application filed September 30, 1 921.

The invention relates to die heads of that type used upon automatic machines for thread cutting and similar operations. Such constructions comprise. essentially a rotary head, a plurality of thread-cutting tools or chasers radially movable in said head and concentric to the axis thereof, means for locking the chasers in an inner position of zuljustinent for the performance of the threading operation, and means for automatically releasing and retractingthe chas= ers when the desired length of thread has been cut.

It is the object of the present invntion to simplify the construction required for the perforu' ance of the essential function as above described and also to render the operation more positive and accurate. Particularly, it is an object to avoid the use of cams. and to so design the parts that they may be manufactured by simple machining operations. With these objects in view the invention consists in the construction as hereinafter set forth.

In the drawings:

Figure 1 is an elevation of the die head;

Figure 2 is a longitudinal section on line E2- 2 of F igureS; I

Figure 3 is a similar View on line 3-3 of Figure 8;

Figure t is a cross-section on line 44 of Figure 3; I

Figure 5 is a longitudinal section on line of Figure 8; I

Figure 6 is a cross-section on line 6-6 of Figure 3;

Figure 7 isan end elevation; and

Figure 8 is a cross-section on line 88 of Figure 3.

A is a cylindrical member having a concentric axial bore series of radially extending slots'or guideways at one end thereof. These slots or guide-ways C are preferably tending from the periphery to the bore and as shown they are four in' number D is a shank member, the 'forwarden'd of slidably engages the bore B, andiE is a or collar on the shank which forms an abut ment for the inner end of the member A. The member Aisfurther provided with a series of longitudinally extending" bores F,

F, G, Hand I Tie bores F andlF form recesses for receiving studs J and J' prdj jecting from the flange E on diametrically B therethrough and a of T-form exwhi h flange Serial No. 504,283.

are springs and abutting against heads on said. studs and at their opposite ends against bushings L and L having a threaded engagement with The studs J and J are preferably threaded to engage nuts M and M and the whole arrangement being one in which the member A is yieldably pressed towards the flange E by the tension of the springs K. Surrounding the member A and longitudinally slidably engaging the same is a sleeve member N having an internal annular groove N near its forward end. This groove has the oppositely inclined faces N and N which are concentric with the axis of the tool and form opposed cones. O are the chasers or thread cutting tools which slidably engage the radial T-shaped guideways ,0 and are held. from disengagement by blocks O engaging the head of the T slot, being secured by the screws 0 The outer endsof the chaser blocks 0 are bevelled at O at the same inclination as the cone face N so that a longitudinal movementof the sleeve N in the direction of the shank will simultaneously bear upon all of the CllfLSGIS O and move the same equally radially inward. The outward movement of the chaser blocks is also positively effected by the longitudinal movement of the sleeve N in the opposite direction. Thisis accomplished through the medium of thrustpins P which slid-ably engage ,bors in the mem-. her extending obliquely both with respect to the axis of the tool and radial'lines from said axisl The inner end of each pin e11 gages a notch Q, in. the chaser block 311d bears against an obliquely inclined face Q. The outer end of each pin is in proximity to the conical face N v and therefore the outward movement of thesleeve N will effect a longitudinal inward movement of the pin P, whichin turn, by its engagement with the member f outward movement of the chaserblock.

To secureexact dimensions in the work the chaser blocks must be moved inward to an exactly predetermined position and for variationin the work this inward liinitmust be correspondingly varied. I have 31O- vided a simple form of adjustable limiting meanscomprising a tOD .Q llarld which has a threaded engagement with the inner endof the sleeve NJ The collar R has the internal the oblique face Q, will cause a radially annular groove It forming a shoulder for engaging a locking dog S radially movable in a recess S in the member A. This dog is yieldably pressed outward by suitable means such as spring 8 and is drawn inward by a trip member T. The latter is in the form of a pin which is secured in a bore in the flange E and projects into a registering bore in the member A intersecting the recess S. The dog S is also slotted for the passage of the pin T therethrough. T is a portion of the pin T which is reduced in diameter and of conical form, and S is an oblique face at the inner end of the slot in the dog S which is engageable with said conical portion T. These several parts cooperate to cause the radial inward movement of the dog 53 againstthe tension of the springs S whenever the memberA is moved longitudinally outward with respect to the shank D. Such a movement will cause the conical portion T of the pin T to ride over the oblique portion S of the dog S, and consequently, will draw the said dog radially inward.

The sleeve N is normally held in its outward position by the tension of springs which are located in the bore in the member A. One end of each of these springs bears against a threaded plug V which closes the end of said bore, while the opposite end of each spring bears against a radian inwardly extending pin W secured to the sleeve N. Thus the tension of the springs U is exerted to hold the sleeve N at its outward. which the pins W abut against the ends of the bore G. On the other hand, these springs will yield to permit the movement of the sleeve N inward. The means for efiecting the inward movement of the sleeve consists of a lever X extending through a slot X in the sleeve and having a ball X thereon for forming a pivotal bearing. The inner end of the lever X has a ball X which engages a suitable fulcrum recess in the member A and the effect of moving the lower end of the lever X inward is therefore to slide the sleeve N inward on the member A. The amount of movement is sufficient to bring the groove R into registration with the dog S, whereupon the springs S will move said dog upward into engagement with the shoulder formed by said groove. The lever X is held from accidental disengagement .by a spring latch consisting of a ball Y in the bore 1, which is pressed against the ball X by a spring Y abutting against a plug Y at the outer end of said bore 1.

In operation, the die head is mounted in a suitable automatic machine for imparting a relative rotation to said head and the work to be threaded in axial alignment therewith. Initially, the chasers are at their outward limit of movement at limits of radial movement so as to clear the work, out by moving the lever X longitudi' nally inward, all of said chasers are simultaneously moved radially inward until "he dog S engages the shoulder of the groove R. The exact dimension of the work is determined by the relation of the shouldered groove R to the cone N and this in turn is determind by the adjustment of the collar It with respect to the sleeve N. Therefore, if the diameter of the work is to be enlarged, the collar B- may be turned so as to crew the same away from the cone H or if the work is to be decreased in diameter, the collar It may be screwed in the opposite direction so as to approach the cone is. buch adjustment is facilitated by providing the collar R with a graduated flange portion ll overlapping the inner end of the sleeve 1: and rotatively adjustable with respect to an index line R thereon.

After the parts are suitably adjusted for the particular dimension of work and the lever X is moved to force the chaser blocks radially inward, the threading operation effected bv the relative rotation of the die head and the work. Atthe desired point a suitable stop (not shown) will arrest the longitudinal movement of the shank member 1), while the continued relative rotation of the head and work will draw outward the member A. This movement is permitted by the yielding of the springs K and K, but as the pin T is attached to the flange E it will remain longitudinally stationary. Tln the cone T on said pin will ride over tl oblique face S of the dog, drawing said dog radially inward and releasing engagement between the same and the shoulder of the groove B. This will permit the springs U to quickly move the sleeve h longitudinally outward, which will withdraw the cone face N from engagement with the oblique faces 0 of the chasers. At the same time the cone face l 3 bearing against the outer ends of the thrust rods P will move the same inward causing the positive actuation of the chaser blocks radially outward. This outward movement is facilitated by providing a slight clearance between the ends of the rods P and the cone N so that the latter will strike a hammer blow, its momentum assisting in overcoming any resistance of the chasers.

It will be understood from the descrip tion as above that the manufacturing of the die head is greatly simplified over that of constructions heretofore used. in the first place, the number of parts is reduced and all of these parts may be formed by simple machining operations such as turning, bor ing and milling. There are no cams or eccentric or irregularly curved surfaces to machine. The construction is also one which secures great accuracy in the work produced and this accuracy is not lost by wear incident to the use of the tool. Therefore, the construction is an exceedingly practical one which fills a long felt want in the art.

hat I claim as my invention is:

1. The combination with a cylindrical head having radially extending guide-ways at the outer end thereof, of chaser blocks slidably engaging said guide-ways, a sleeve surrounding said head and longitudinally slidable thereon, being provided with an annular groove forming a conical inner face for engaging the outer ends of said chaser blocks, an extension for said sleeve adjustable longitudinally with respect thereto, and a locking dog for engaging said extension to hold said chaser blocks at a predetermined inner limit of adjustment.

2. The combination with a cylindrical head having radially extending guide'ways at the outer end thereof, chaser blocks slidably engaging said guideavays, and a sleeve surrounding said head and longitudinally slidable thereon, said sleeve being provided with an annular groove forming an uninterrupted conical inner face for engaging the outer ends of said chaser blocks, said conical face being adapted to permit movement of said chaser blocks without rotational movement of said sleeve.

3. The combination with a cylindrical head having radial guide-ways at the outer end thereof, of chaser blocks slidably engaging said radial guideways, a sleeve surrounding said head and grooved to provide a conical face for engaging the outer ends of said chaser blocks to move the same radially inward when said sleeve is moved longitudinally on said head in one direction, and means interposed between said sleeve and chaser blocks for positively moving the latter radially outward when said sleeve is moved longitudinally in the opposite direction.

4. The combination with a cylindrical head having radial guide-Ways at the outer end thereof, of chaser blocks slidably engaging said radial guide-ways, a sleeve surrounding said head and longitudinally slidable thereon, said sleeve having an internal groove providing oppositely inclined cone faces, one of said faces engaging the outer ends of said chaser blocks to move the same radially inward in one direction of movement of the sleeve, and thrust rods slidable in said head and extending between the opposite cone face of said sleeve and the respective chaser blocks in a direction to move said blocks radially outward when said sleeve is moved to relieve pressure on the outer ends of said chaser blocks.

The combination with a cylindrcial head having radial guide-Ways at one end thereof. of chaser blocks slidably engaging said radial guide-ways, a sleeve surrounding said head and longitudinally slidable thereon, said sleeve having an anular groove providing oppositely inclined cone faces, one of said faces engaging the outer ends of said chaser blocks to move the same radially inward when the sleeve is moved longitudinally in one direction and rods slidable in said head, each extending in a direction oblique to one of said radial guides, the outer ends of said rods being in operative relation to the opposite cone face of said sleeve, and the inner ends engaging the respective chaser blocks to impart thereto a radial outward movement.

6. The combination with a cylindrical head having a radial guide-way therein, of a block slidably engaging said guide-way, a sleeve surrounding said head and longitudinally slidable thereon, said sleeve being grooved to provide oppositely inclined faces oblique to the axis of said head, one of said faces engaging the outer end of said block to move the same radially inward, and a thrust rod slidable in said head arranged in a direction which is oblique to said radial guide and transverse to the opposite oblique face in said sleeve, said rod being actuated by said sleeve when moved in a direction to relieve pressure on the outer end of said block, and the inner end of said rod actuating said block in a radially outward direction.

7. The combination with a head having a radially extending guide-way therein, of a block slidably engaging said guide-way, a sleeve surrounding said head and longitudinally slidable thereon, said sleeve being grooved to form oppositely inclined faces, one of said faces engaging the outer end of said block to move the same radially inward, a thrust rod slidable in said head in a direction transverse to the opposite of said oblique faces and oblique to said radial guide, the inner end of said rod engaging an oblique face on said block to move the same radially outward.

8. The combination with a head having a radial guide-way therein, of a block slidably engaging said guidewvay, a sleeve surrounding said head and grooved to form oppositely inclined oblique faces, one of said faces engaging the outer end of said block to move the same radially inward when said sleeve is moved longitudinally in one direction, and means for positively moving said block radially outward when said sleeve is moved longitudinally in the opposite direction, said means comprising a rod extending transverse to the opposite of said oblique faces of the sleeve and in a direction oblique to said radial guide, and an oblique face on said block engaged by the inner end of said rod.

9. The combination with a head having a radial guide-way therein, of a block slidably engaging said guide-way, a sleeve surrounding said head having a conical face for enthe outer end of said block to move the same radially inward upon the longitudinal movement of said sleeve, said sleeve having also an oppositely inclined conical face, and means interposed between said opposite face and said block to move the latter radially outward when said sleeve is moved to relieve pressure on the outer end of said block, said means providing a slight clearance to impart an impact from said sleeve thereto.

10. The combination with a hollow cylindrical head having a radial guide-way therein, of a shank longitudinally slidably engaged by said head, a flange on said shank forming an abutment for one end of said. head, a block slidably engaging said radial guide-way, a sleeve surrounding said head and grooved to form a conical face for engaging the outer end of said block to move the same radially inward when said sleeve is moved longitudinally, a dog radially slidable in said head and engageable with a locking shoulder in said sleeve, and means operated by an outward movement. of said head away from said abutment flange for withdrawing said dog from engagement with said locking shoulder.

11. The combination with a head having radial guide-ways therein and blocks slidably engaging said guide-ways, of a sleeve surrounding said head and having a conical face for engaging the outer ends of said blocks to move the same radially inward, a shank on which said head is longitudinally slidably mounted, a flange on Said shank forming an abutment for the inner end of said head, means for resiliently pressingvsaid head against said abutment, a dog radially slid-able in said head and engageable with a locking shoulder 1n sald sleeve to hold the latter from. longitudinal movement, a pin secured to said abutment flange extending through an aperture in said dog and provided with an oblique face "for withdrawing said dog from engagement with said locking shoulder upon the relative longitudinal movement of said head and shank.

12. The combination with a shank having a flange or collar thereon, of a cylindrical head slidable upon said shank and abutting against said flange or collar, studs secured to and projecting from said flange to engage longitudinal recesses in said head on diametrically opposite sides thereoit, springs sleeved on said studs and abutting against shoulders thereon at one end, bushings in said recesses surrounding said studs and forming abutments for the opposite ends of said springs, blocks slidably engaging radial guides in said head, a sleeve surrounding said head and having a conical face for engaging said blocks to actuate the same radially, pins projecting inward from said sleeve through slots in said head and intersecting longitudinal recesses in said head, springs housed within said recesses abutting at one end against said pins and at their opposite ends against stationary abutments in said head, a dog radially movable in said head and engageable with a locking recess in said sleeve, and a pin secured to said flange 0r abutment projecting thereit'ron'i and slidably engaging a registering aperture in said head, said pin having a conical portion for engaging said dog to actuate the same radially inward when said head is moved lo1igi tudinally with respect to said shank.

In testimony whereof I atiix my signature.

CONRAD JOBS? 

